Glen Canyon Dam at a Glance Forever changed, just how is the river adjusting to this dam? Behind Glen Canyon Dam in Page, Arizona is the second-largest man-made lake in the United States: Lake Powell. Glen Canyon Dam serves in a number of capacities for those dependent on it, including flood protection, water supply and electrical generation. There is, however, a flip side to the benefits: alteration to the downstream environment. Historically, since its conception in the early 20th Century, Glen Canyon Dam has been the center of controversy. The late David Brower opposed it from the onset and helped to raise awareness about the fragility of the surrounding ecosystem. Since then, numerous changes have resulted in the operation of the dam including the Adaptive Management Program (AMP) – an advisory body to oversee both the policy and the science of the dam. However, challenges still exist. This issue of River Report examines the history of Glen Canyon Dam including the reforms to dam operation, establishment of the AMP and the future of both the AMP and dam operations.